Scroll compressor with vapor injection

ABSTRACT

A fitting is secured to a shell of an apparatus. A tube is fixedly and sealingly attached to the fitting by either forming the fitting into engagement with the tube or forming the tube into engagement with the fitting. In both embodiments, engagement between the tube and a contoured surface defined by the fitting creates the fixed and sealed attachment.

FIELD OF THE INVENTION

The present invention relates to scroll type machines. Moreparticularly, the present invention relates to scroll compressorsincorporating a vapor injection system which utilizes a crimped tubedesign for the piping of the fluid injection system.

BACKGROUND AND SUMMARY OF THE INVENTION

Refrigeration and air conditioning systems generally include acompressor, a condenser, an expansion valve or equivalent, and anevaporator. These components are coupled in sequence in a continuousflow path. A working fluid flows through the system and alternatesbetween a liquid phase and a vapor or gaseous phase.

A variety of compressor types have been used in refrigeration systems,including but not limited to reciprocating compressors, screwcompressors and rotary compressors. Rotary compressors can both includethe vane type compressors, the scroll machines as well as other rotarymachines. Scroll machines are constructed using two scroll members witheach scroll member having an end plate and a spiral wrap. The spiralwraps are arranged in an opposing manner with the two spiral wraps beinginterfitted. The scroll members are mounted so that they may engage inrelative orbiting motion with respect to each other. During thisorbiting movement, the spiral wraps define a successive series ofenclosed spaces, each of which progressively decreases in size as itmoves inwardly from a radially outer position at a relatively lowsuction pressure to a central position at a relatively high pressure.The compressed gas exits from the enclosed space at the central positionthrough a discharge passage formed through the end plate of one of thescroll members.

Refrigeration systems are now incorporating fluid injection systemswhere a portion of the refrigerant is injected into the enclosed spacesat a pressure which is intermediate the low suction pressure and therelatively high pressure or what is termed discharge pressure. Thisrefrigerant is injected into the enclosed spaces through injection portsextending through one of the two scroll members. The injection of thisrefrigerant has the effect of cooling the compressor and/or increasingboth system capacity and the efficiency of the compressor. The sourcefor supplying the intermediate pressurized refrigerant is typicallyprovided from a different portion of the refrigeration system which islocated outside of the hermetic shell of the compressor. Typically aflash tank, an economizer, an accumulator or a different component inthe refrigerant cycle is the source for the intermediate pressurizedrefrigerant.

When developing the fluid injection system, the development engineermust ensure that the intermediate pressurized refrigerant that is beinginjected is routed from the component outside the hermetic shell,through the hermetic shell and to the fluid injection ports. Piping ortubing extends between the component supplying the intermediatepressurized refrigerant to a pipe or tube fitting that is sealinglysecured to and that extends through the hermetic shell of the compressorassembly and then to an internal pipe or tube which extends between thepipe or tube fitting and the injection port on one of the components ofthe compressor. When the pipe or tube is assembled or connected betweenthe injection port and the pipe or tube fitting on the hermetic shell,the connection must be a sealed connection to avoid the leaking of therefrigerant to the internal space of the hermetic shell and to theenvironment.

Thus, the continued development of fluid injection systems is directedtowards providing more efficient and lower cost connection designs foruse between the pipe or tubing and the pipe or tubing fitting.

The present invention provides the art with a fluid injection systemwhich utilizes a crimped fitting for the attachment of the pipe or tubeto the pipe or tube fitting. The refrigerant tube is assembled to thefitting and then a tool engages the fitting and/or the tube to create asealed connection without having to solder or braze the connection.

Further areas of applicability of the present invention will becomeapparent from the detailed description provided hereinafter. It shouldbe understood that the detailed description and specific examples, whileindicating the preferred embodiment of the invention, are intended forpurposes of illustration only and are not intended to limit the scope ofthe invention.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention will become more fully understood from thedetailed description and the accompanying drawings, wherein:

FIG. 1 is a vertical cross-section of a scroll compressor incorporatingthe unique fluid injection system in accordance with the presentinvention;

FIG. 2 is a horizontal sectional view of the scroll compressor of thepresent invention taken just below the partition in FIG. 1;

FIG. 3 is a plan view of the non-orbiting scroll of the presentinvention viewed from the vane side of the non-orbiting scroll;

FIG. 4 is a plan view of the scroll members positioned at the point ofinitially sealing off the first enclosed space;

FIG. 5 is a plan view of the scroll members positioned at the point ofinitially sealing off the second enclosed space;

FIG. 6 is a plan view of the scroll members positioned at the pointwhere the vapor injection port is open to two enclosed spaces;

FIG. 7 is an enlarged cross-sectional view of the through-the-shellfitting prior to the forming operation;

FIG. 8 is a view similar to FIG. 7, but after the forming operation usedto create the connection for the through-the-shell fitting;

FIG. 9 is an enlarged cross-sectional view of the through-the-shellfitting in accordance with another embodiment of the present invention;and

FIG. 10 is a view similar to FIG. 9, but after the forming operationused to create the connection for the through-the-shell fitting.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The following description of the preferred embodiment(s) is merelyexemplary in nature and is in no way intended to limit the invention,its application, or uses.

Referring now to the drawings in which like reference numerals designatelike or corresponding parts throughout the several views, there is shownin FIG. 1, a scroll compressor which incorporates the unique fluidinjection system in accordance with the present invention and which isdesignated generally by the reference numeral 10. The followingdescription of the preferred embodiment is merely exemplary in natureand is no way intended to limit the invention, its application or itsuses.

Scroll compressor 10 comprises a generally cylindrical hermetic shell 12having welded at the upper end thereof a cap 14 and at the lower endthereof a base 16 having a plurality of mounting feet (not shown)integrally formed therewith. Cap 14 is provided with a refrigerantdischarge fitting 18 which may have the usual discharge valve therein(not shown). Other major elements affixed to shell 12 include atransversely extending partition 20 which is welded about its peripheryat the same point cap 14 is welded to shell 12, an inlet fitting 22, amain bearing housing 24 which is suitably secured to shell 12 and alower bearing housing 26 having a plurality of radially outwardlyextending legs each of which is suitably secured to shell 12. A motorstator 28 which is generally square in cross-section but with thecorners rounded off is press fit into shell 12. The flats between therounded corners on motor stator 28 provide passageways between motorstator 28 and shell 12 which facilitate the return flow of the lubricantfrom the top of shell 12 to its bottom.

A drive shaft or crankshaft 30 having an eccentric crank pin 32 at theupper end thereof is rotatably journaled in a bearing 34 in main bearinghousing 24 and in a bearing 36 in lower bearing housing 26. Crankshaft30 has at the lower end thereof a relatively large diameter concentricbore 38 which communicates with a radially outwardly located smallerdiameter bore 40 extending upwardly therefrom to the top of crankshaft30. Disposed within bore 38 is a stirrer 42. The lower portion of theinterior shell 12 is filled with lubricating oil and bores 38 and 40 actas a pump to pump the lubricating oil up crankshaft 30 and ultimately toall of the various portions of compressor 10 which require lubrication.

Crankshaft 30 is rotatably driven by an electric motor which includesmotor stator 28 having motor windings 44 passing therethrough and amotor rotor 46 press fitted onto crankshaft 30 and having upper andlower counterweights 48 and 50, respectively. A motor protector 52, ofthe usual type, is provided in close proximity to motor windings 44 sothat if the motor exceeds its normal temperature range, motor protector52 will de-energize the motor.

The upper surface of main bearing housing 24 is provided with an annularflat thrust bearing surfaces 54 on which is disposed an orbiting scrollmember 56. Orbiting scroll member 56 comprises an end plate 58 havingthe usual spiral valve or wrap 60 on the upper surface thereof and anannular flat thrust surface 62 on the lower surface thereof. Projectingdownwardly from the lower surface is a cylindrical hub 64 having ajournal bearing 66 therein and in which is rotatively disposed a drivebushing 68 having an inner bore within which crank pin 32 is drivinglydisposed. Crank pin 32 has a flat on one surface (not shown) whichdrivingly engages a flat surface in a portion of the inner bore of drivebushing 68 to provide a radially compliant drive arrangement such asshown in assignee's U.S. Pat. No. 4,877,382, the disclosure of which isincorporated herein by reference.

Wrap 60 meshes with a non-orbiting scroll wrap 72 forming part of anon-orbiting scroll member 74. During orbital movement of orbitingscroll member 56 with respect to non-orbiting scroll member 74 createsmoving pockets of fluid which are compressed as the pocket moves from aradially outer position to a central position of scroll members 56 and74. Non-orbiting scroll member 74 is mounted to main bearing housing 24in any desired manner which will provide limited axial movement ofnon-orbiting scroll member 74. The specific manner of such mounting isnot critical to the present invention.

Non-orbiting scroll member 74 has a centrally disposed discharge port 76which is in fluid communication via an opening 78 in partition 20 with adischarge chamber 80 defined by cap 14 and partition 20. Fluidcompressed by the compression chambers or moving pockets between scrollwraps 60 and 72 discharges into discharge chamber 80 through port 76 andopening 78. Non-orbiting scroll member 74 has in the upper surfacethereof an annular recess 82 having parallel coaxial sidewalls withinwhich is sealing disposed for relative axial movement an annular sealassembly 84 which serves to isolate the bottom of recess 82 so that itcan be placed in fluid communication with a source of intermediate fluidpressure by means of a passageway 86. Non-orbiting scroll member 74 isthus axially biased against orbiting scroll member 56 by the forcescreated by discharge pressure acting on the central portion ofnon-orbiting scroll member 74 and the forces created by intermediatefluid pressure acting on the bottom of recess 82. This axial pressurebiasing, as well as the various techniques for supporting non-orbitingscroll member 74 for limited axial movement, are disclosed in muchgreater detail in assignee's aforementioned U.S. Pat. No. 4,877,382.

Relative rotation of scroll members 56 and 74 is prevented by the usualOldham coupling 88 having a pair of key slidably disposed indiametrically opposing slots in non-orbiting scroll member 74 and asecond pair of keys slidably disposed in diametrically opposed slots inorbiting scroll member 56.

Compressor 10 is preferably of the “low side” type in which suction gasentering shell 12 is allowed, in part, to assist in cooling the motor.So long as there is an adequate flow of returning suction gas, the motorwill remain within the desired temperature limits. When this flowceases, however, the loss of cooling will cause motor protector 52 totrip and shut compressor 10 down.

The scroll compressor, as thus broadly described, is either known in theart or it is the subject matter of other pending applications for patentby Applicant's assignee. The details of construction which incorporatethe principles of the present invention are those which deal with aunique fluid injection system identified generally by reference numeral100. Fluid injection system 100 is used to inject refrigerant forcooling and/or increasing the capacity and efficiency of compressor 10.

Referring now to FIGS. 1-3, fluid injection system 100 comprises a fluidinjection passage 102 extending through an end plate of non-orbitingscroll member 74, a single fluid injection port 104 opening into theenclosed fluid pockets, a connecting tube 106, a fluid injection port108 extending through shell 12 a fluid injection fitting 110 secured tothe outside of shell 12, and a connecting tube 112 located between fluidinjection fitting 110 and the source of intermediate pressurized fluid.

Fluid injection passage 102 is a cross drilled feed hole which extendsgenerally horizontal through non-orbiting scroll member 74 from aposition on the exterior of non-orbiting scroll member 74 to a positionwhere it communicates with fluid injection port 104. Fluid injectionport 104 extends generally vertically from passage 102 throughnon-orbiting scroll member 74 to open into the enclosed spaces orpockets formed by wraps 60 and 72 as detailed below. Connecting tube 106extends from fluid injection passage 102 to fluid injection port 108where it extends through fluid injection port 108 to be sealinglysecured to fluid injection fitting 110. While not shown, the source ofthe intermediate pressurized refrigerant fluid from a refrigerationsystem (not shown) is in communication with fluid injection fitting 110through connecting tube 112 to provide the refrigerant fluid forinjecting.

Referring now to FIGS. 4 and 5, the positioning of fluid injection port104 is illustrated in relation to scroll wraps 60 and 72. As can be seenin FIGS. 4 and 5, scroll wraps 60 and 72 are asymmetrically designed.Non-orbiting scroll wrap 72 extends an additional angular amount toprovide the asymmetrical profile. In the preferred embodiment,non-orbiting scroll wrap 72 extends 170° further than orbiting scrollwrap 60. The asymmetrical profile of scroll wraps 60 and 72 causes thetwo fluid pockets created by wraps 60 and 72 to be initially sealed offat different positions or at different times during the orbiting motionof orbiting scroll member 56. FIG. 4 illustrates the initial sealingpoint of an enclosed space 120 which is sealed when an outer surface 122of orbiting scroll wrap 60 engages an inner surface 124 of non-orbitingscroll wrap 72. Just prior to the time of sealing enclosed space 120,fluid injection port 104 is sealed off or closed by orbiting scroll wrap60 as shown in FIG. 4. This ensures that there will not be anyintermediate pressurized refrigerant fluid that is allowed to migrate tothe suction chamber of compressor 10. Simultaneous with the sealing ofenclosed space 120 by surfaces 122 and 124, orbiting scroll wrap 60begins to uncover or open fluid injection port 104 to begin theinjection of refrigerant fluid into enclosed space 120. While FIG. 4 isillustrated with fluid injection port 104 opening simultaneous with thesealing of enclosed space 120, it is within the scope of the presentinvention to open fluid injection port 104 prior to or subsequent to thesealing of enclosed space 120 if desired.

FIG. 5 illustrates the initial sealing point of an enclosed space 130which is sealed when an inner surface 132 of orbiting scroll wrap 60engages an outer surface 134 of non-orbiting scroll wrap 72. Just priorto the time of sealing enclosed space 130, fluid injection port 104 issealed off or closed by orbiting scroll wrap 60 as shown in FIG. 5. Thisensures that there will not be any intermediate pressurized refrigerantfluid that is allowed to migrate to the suction chamber of compressor10. Simultaneous with the sealing of enclosed space 130 by surfaces 132and 134, orbiting scroll wrap 60 begins to uncover or open fluidinjection port 104 to begin the injection of refrigerant fluid intoenclosed space 130. While FIG. 5 is illustrated with fluid injectionport 104 opening simultaneous with the sealing of enclosed space 130, itis within the scope of the present invention to open fluid injectionport 104 prior to or subsequent to the sealing of enclosed space 130 ifdesired.

As can be seen in FIG. 6, the size of fluid injection port 104 issignificantly larger than the width of orbiting scroll wrap 60. Thismeans that during a portion of the cycle for orbiting scroll member 56,fluid injection port 104 will be open to both enclosed space 120 andenclosed space 130. This does not present a problem to the operation andfunction of fluid injection system 100 because the pressure ofrefrigerant fluid at fluid injection port 104 is always larger than thepressure of refrigerant in enclosed spaces 120 and 130. The increasedsize for fluid injection port 104 allows for the unique ability of asingle port being able to open to both enclosed spaces 120 and 130simultaneous to the sealing of the respective enclosed space. Inaddition, the increased size of fluid injection port 104 allows for theinjection of an increased amount of intermediate pressurized gas toincrease the capacity and efficiency of compressor 10.

Referring now to FIGS. 7 and 8, attachment of connecting tube 106 tofluid injection fitting 110 is illustrated in greater detail. Fluidinjection fitting 110 is a metal component that is attached to shell 12using a brazing, soldering or welding process or by any other processknown in the art. Fluid injection fitting 110 defines a circularextension 140 which is disposed within fluid injection port 108extending through shell 12. A contoured surface in the form of a groove142 extends into circular extension 140 within which connecting tube 106is located. An inner diameter 144 of circular extension 140 is formed tocreate deformations 146 in both fluid injection fitting 110 andconnecting tube 106 to retain and seal the connection between fluidinjection fitting 110 and connecting tube 106. Deformations 146 inconnecting tube 106 cause engagement between connecting tube 106 and theoutside diameter of groove 142 and deformations on inner diameter 144cause engagement between fluid injection fitting 110 and connecting tube106.

FIGS. 7 and 8 illustrate the process used to form the inner diameter144. Connecting tube 106 is first located within groove 142 of circularextension 140. Next, a forming tool 148 is inserted into the open end offluid injection fitting 110 and an expandable die portion 150 of formingtool 148 forms the inner diameter 144 of fluid injection fitting 110 tocreate deformations 146. There can be multiple deformations 146 formedaround the circumference of inner diameter 144 or there can be onecontinuous deformation 146 extending around the entire circumference ofinner diameter 144.

Referring now to FIGS. 9 and 10, attachment of connecting tube 106 to afluid injection fitting 210 is illustrated. Fluid injection fitting 210is a metal component that is attached to shell 12 using a brazingprocess or by any other process known in the art. Fluid injectionfitting 210 defines a circular extension 240 which is disposed withinfluid injection port 108 extending through shell 12. A contoured surface242 is formed within circular extension 240. The end of connecting tube106 is formed into contoured surface 242 to create a deformation toretain and seal the connection between fluid injection fitting 210 andconnecting tube 106.

FIGS. 9 and 10 illustrate the process used to form the end of connectingtube 106. Connecting tube 106 is first located within circular extension240 of fluid injection fitting 210 adjacent contoured surface 242 asillustrated in FIG. 9. Next a forming tool 248 having a contouredsurface 250 is inserted into the open end of fluid injection fitting210. Contoured surface 250 of tool 248 corresponds to contoured surface242 of fluid injection fitting 210. Contoured surface 250 of formingtool 248 engages the end of connecting tube 106 to expand or form theend of connecting tube 106 onto contoured surface 242 of fluid injectionfitting 210 to retain and seal the connection.

The description of the invention is merely exemplary in nature and,thus, variations that do not depart from the gist of the invention areintended to be within the scope of the invention. Such variations arenot to be regarded as a departure from the spirit and scope of theinvention.

1. An apparatus comprising: a shell; a fitting secured to said shell,said fitting defining an inner diameter and a contoured surface disposedradially outward from said inner diameter; a tube extending through saidinner diameter, one of said tube and said fitting defining a deformationwhich fixedly secures said tube to said fitting.
 2. The apparatusaccording to claim 1, wherein said contoured surface forms a grooveextending into said fitting, said tube being disposed within saidgroove.
 3. The apparatus according to claim 2, wherein said innerdiameter of said fitting defines said deformation such that said fittingengages an inside diameter of said tube.
 4. The apparatus according toclaim 1, wherein said tube defines said deformation such that an outsidediameter of said tube engages said fitting.
 5. The apparatus accordingto claim 1, further comprising a compressor disposed within said shell,said tube extending between said fitting and said compressor.
 6. Theapparatus according to claim 5, wherein said contoured surface forms agroove extending into said fitting, said tube being disposed within saidgroove.
 7. The apparatus according to claim 6, wherein said innerdiameter of said fitting defines said deformation such that said fittingengages an inside diameter of said tube.
 8. The apparatus according toclaim 5, wherein said tube defines said deformation such that an outsidediameter of said tube engages said fitting.
 9. The apparatus accordingto claim 5, wherein said tube is in communication with a compressionchamber defined by said compressor.
 10. The apparatus according to claim5, further comprising a fluid injection system communicating with saidcompressor, said tube forming a part of said fluid injection system. 11.The apparatus according to claim 1, further comprising: a first scrollmember disposed within said shell, said first scroll member having afirst spiral wrap extending from a first end plate; a second scrollmember disposed within said shell, said second scroll member having asecond spiral wrap extending from a second end plate, said second scrollmember being intermeshed with said first scroll wrap, said first spiralwrap engaging said second spiral wrap to define at least one compressionchamber; wherein said tube extends between said fitting and one of saidfirst and second scroll members.
 12. The apparatus according to claim11, wherein said contoured surface forms a groove extending into saidfitting, said tube being disposed within said groove.
 13. The apparatusaccording to claim 12, wherein said inner diameter of said fittingdefines said deformation such that said fitting engages an insidediameter of said tube.
 14. The apparatus according to claim 11, whereinsaid tube defines said deformation such that an outside diameter of saidtube engages said fitting.
 16. The apparatus according to claim 11,further comprising a fluid injection system communicating with said oneof said first and second scroll members, said tube forming a part ofsaid fluid injection system.
 17. A method for fixedly attaching a tubeto a shell, the method comprising: attaching a fitting to said shell;positioning a tube adjacent a contoured surface defined by said fitting;forming a deformation in one of said tube and said fitting to fixedlyattaching said tube to said fitting by having engagement between saidtube and said contoured surface.
 18. The apparatus according to claim17, wherein said attaching step includes brazing, soldering or weldingsaid fitting to said shell.
 19. The apparatus according to claim 17,wherein said forming step includes forming said fitting into engagementwith an inside diameter of said tube.
 20. The apparatus according toclaim 17, wherein said forming step includes forming said tube to engagean outside diameter of said tube with said contoured surface.